From mboxrd@z Thu Jan 1 00:00:00 1970 From: van.freenix@gmail.com (Peng Fan) Date: Tue, 3 Nov 2015 20:59:17 +0800 Subject: [RFC] iommu: arm-smmu: correct reference count Message-ID: <1446555557-3097-1-git-send-email-van.freenix@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org iommu_group_alloc will initialize the reference count for group to 1. iommu_group_add_device also increase the group reference count, if nothing bad happends. And we need to add iommu_group_put to decrease the reference count for group. Signed-off-by: Peng Fan Cc: Will Deacon Cc: Joerg Roedel --- Not sure whether my understanding is correct or not. I checked rockchip-iommu.c exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after iommu_group_add_device. drivers/iommu/arm-smmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 48a39df..1cab720 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1344,6 +1344,7 @@ static int arm_smmu_add_platform_device(struct device *dev) struct iommu_group *group; struct arm_smmu_master *master; struct arm_smmu_device *smmu = find_smmu_for_device(dev); + int ret; if (!smmu) return -ENODEV; @@ -1358,7 +1359,11 @@ static int arm_smmu_add_platform_device(struct device *dev) return PTR_ERR(group); iommu_group_set_iommudata(group, &master->cfg, NULL); - return iommu_group_add_device(group, dev); + + ret = iommu_group_add_device(group, dev); + iommu_group_put(group); + + return ret; } static int arm_smmu_add_device(struct device *dev) -- 1.8.4